JPS6097894A - Pen ball made of zirconia - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

INDUSTRIAL FIELD OF APPLICATION The present invention relates to an element for liquid transfer, in particular a ball for transferring ink from nine ink reservoirs to a writing surface, i.e. multi-axis rotation or free movement, as in the well-known ballpoint pen. Mounted inside the socket so that it can rotate (
The present invention relates to a ball which is pulled up and whose rear part is connected to an ink storage part. Prior Art and Its Problems There are two basic types of ballpoint pens that are manufactured. The first type uses oil-based high viscosity ink, and the second type uses water-based low viscosity ink. The latter type is D −') n'j
It is called a rolling ball pen. The balls commonly used in these pens are generally made of stainless steel or bonded tungsten carbide. Pens that use a ball are easy to configure and operate, but
It often leads to functional impairment in several respects. For example, the ink may not wet the ball, the friction of the ball against the writing surface may be too low to cause the ball to rotate, or the surface of the ball may be too rough, causing wear on the socket. The wear resistance of the ball may be too low, or the chemical reaction between the material that makes up the ball and the ink composition may cause corrosion of the ball and/or ball socket. . Of these disorders, corrosion is the most difficult to overcome. Corrosion may occur uniformly, where the ball (usually metal) corrodes at a constant rate over its entire surface. Corrosion may also occur only in certain areas of the surface;

[;L1 Corrosion may occur relatively quickly on the area. Of these two types of corrosion, localized corrosion is the most troublesome. Five types of localized corrosion are generally recognized, and these are due to stress distortion resulting from, for example, cold working, heat treatment, or external stresses during pen use. Types of corrosion include pitting, which is thought to be due to the presence of cotton dust and dust; crack-like corrosion, which is thought to be caused by metal-to-gold contact; and corrosion, which is thought to be caused by different metals coming into contact with the electrolyte. Electrolytic corrosion: There is intergranular corrosion. This corrosion occurs on unannealed austenitic stainless steel balls. Chromium in the stainless steel may precipitate as chromium carbide at grain boundaries. Grain boundary carpions act to remove chromium from adjacent regions, rendering those regions susceptible to corrosion in certain environmental regimes. Additionally, corrosion is caused by or affected by impurities in the ball, and the environmental temperature generally increases corrosion activity. The degree of ventilation to the ball usually affects the rate of corrosion, and corrosive agents (
The velocity of the ball surface relative to the ink, socket, etc.) often influences the corrosion rate. By knowing the behavior of conventional ball elements as liquid transfer elements in ballpoint pens, it can be understood that many types of corrosion occur with ball elements containing gold or metal. Probably. Such metal sheaths are known in the art to include, for example, 440C stainless steel, 440C stainless steel, and 440C stainless steel.
40G super hard stainless steel. G E 44A tungsten carbide (tungsten carbide particles bonded by cobalt), and GE65
7 (tungsden carbide, cobalt J5 and chromium). The latter two monthly rates are commercially available from General Electric Company. Other ball materials have also been proposed in the ballpoint pen art, such as glass, ceramic, austenitic stainless steel, and coated ceramic. Some tests have shown that coated ceramics have high wear resistance and also good resistance to corrosion. Although austenitic stainless steel has high corrosion resistance, it is too soft and does not have the wear resistance required for a ballpoint pen ball. Ceramics have been considered as a preferred material for constructing pen balls, but until the invention was achieved, ceramics lacked the necessary physical properties, one of which was low porosity. ). In addition, ceramic materials such as polyurethane are highly abrasive and are therefore unsuitable.Recently, in the United States,
A ballpoint pen made in Japan using a ball called ball J is commercially available. Chemical analysis shows that the ball is composed of silicon carbide. SUMMARY OF THE INVENTION In accordance with the present invention, a liquid transfer ball useful as a ballpoint pen ball is formed from an at least partially stabilized zirconia-based ceramic. Zirconia-based ceramic balls according to the present invention are formed from sintered zirconia particles, where sintering refers to sintering without the use of melting and other known methods (e.g., shaping and/or pressing). Particles are directly bonded to each other to form an unfired body (green body), which is then fired to form a sintered hot stone. One method for forming the liquid transfer ball of the present invention is to heat a conventional zirconia dispersion ball by hot isostatic pressing.
)It is to be. Alternatively, the liquid transfer balls of the present invention can be formed using conventional techniques by forming at least partially stabilized zirconia dispersion balls, but the zirconia particles The average particle size of is kept fairly small. Each of these methods forms the liquid transfer ball element of the present invention and provides a ceramic ball that can be used as a ballpoint pen ball. The porosity of the final ball is significantly reduced compared to conventional zirconia dispersion balls. That is, about 20
% by volume to less than 8%. This reduction in porosity allows the ball, after polishing, to be used as a liquid (ink) transport element in a ballpoint pen. A pen using the ball of the present invention is a rolling ballpoint pen, tk
In other words, it is particularly useful for pens that use water-based low viscosity ink (as conventional ballpoint pens, type b uses oil 11 high viscosity ink). However, it should be understood that the present invention can equally be applied to ballpoint pens using relatively high viscosity inks with the desired effect. In order to limit the porosity of the balls as described above, the batch solids used in the slip for obtaining the zirconia-based ceramic are crushed by subjecting them to a vibratory mill operation in one production T culm. The average particle size is between 0.5 and 1 micron. The surface roughness after polishing (arithmetic mean value) is
For rolling ballpoint pens, it is in the range of 0.10 to 0.15 microns, and for J, high viscosity 11 ink pens, it is in the range of 0.04 to 0.05 microns. Optical image analysis (optlcal tma(1(3alla)
Zirco 1 nia pen ball lots with an average porosity of less than about 2% as measured by
It can be processed to any range from 4 to 0.05 microns and from 0.10 to 0.15 microns, and is therefore suitable for any type of pen. 3
A ball lot with a porosity in the range of ~8% is
It can be processed to 0.15 mm, suitable for use in rolling ballpoint pens. Balls with porosity greater than about 8 volume percent are finished to a roughness greater than 0.15 microns. Pens with balls like this can create undesirable scratches during writing and can also cause excessive wear on the socket 1. However, rough balls are better for writing on flat or slippery surfaces, and in certain applications: 1. :i Such a ball may exhibit desirable properties. Besides porosity, an important factor for pen balls is strength. The ball must withstand the stresses imposed during pen assembly and use without breaking. The zirconia pen ball of the present invention has a breaking strength of over 60 bond and satisfies these requirements. When the roughness is the same, the zirconia pen ball of the present invention is
(For rolling ballpoint pens), the rate at which the seams 1 to 1 of the pen 11 wear out is considerably lower than that of the bonded tungsten carbide ball. No chemical or electrical corrosion was observed in these zirconia pen balls. Also, the wear of the zirconia ball during writing is negligible. j: Also, the ball of the present invention has improved line quality (1ine quality) than the tungsten carbide ball, and the length of the line (q) is longer. It is believed that this is related to the wetting properties.The balls of the present invention are suitable for water-based inks.
Can be used to write on any slippery surface. Furthermore, the ball of the present invention has a speed of 11n per second,
It was possible to write continuously with a current transmission of more than 100%, which was faster than any of the other pen ball materials tested. The homogeneity of the balls obtained by finishing from lots of zirconia blanks is superior to that obtained from lots 1 of tungsten carbide blanks, and it is less expensive to finish finishing similarly sized blanks. there were. 12- To summarize the above, several characteristics of zirconia ceramics contribute to its behavior as a pen ball, including excellent lubricity, wettability with ink, abrasion resistance, and corrosion resistance. It is considered to be something that gives. The basic properties considered important for the zirconia ball of the present invention to be used in a pen are (1) low porosity, and (2) necessary strength. When used in rolling ballpoint pens, the zirconia balls are preferably finished to a roughness of about 0.10 to 0.15 microns, which results in balls having porosity ranging from 0 to about 8 percent. make sure you get it. When used in high viscosity ink pens, the values are 0.04 to 0.05 microns and 0 to about 2%. Therefore, when a 1.5# ball blank (unpolished ball) according to the present invention is compressed between bonded tungsten carbide anvils (crosshead speed is approximately 0.2 mm/min), the fracture strength exceeds 60 pounds. ing. DETAILED DESCRIPTION OF THE INVENTION The method of manufacturing near balls is known in the art, for example, as used in high speed dispersion mills to disperse paint and ink pigments. (Prior art ball: its manufacturing method) Zirconia-based paint/pigment dispersion medium (71
The sol-gel method (the
The method called sol-get process was developed by Ning Glass Co., Ltd., the applicant of the present invention.
About 20 by rningG 1ass WORKS)
It has been carried out for years. Balls produced in this way are used, for example, as dispersion media in the production of paints and for grinding purposes. This method is illustrated in FIG. 1 and described below. The obtained product [U, 0
．． A ball having a diameter ranging from 5 to 3.4 mm,
It is almost completely opaque and typically has a porosity of about 20 volume percent as determined by image analysis of the polished area. Because of this high porosity, the ball could not be polished to a sufficiently smooth surface to be used as a pen ball. This is because polishing removes the non-permeable surface layer and exposes the highly porous portion inside the ball. This traditional sol-gel method combines an aqueous solution of a soluble alginate (ammonium alginate or mono-lium alginate) with a specific polyvalent metal salt (e.g. alkaline earth gold halide, Ca C9,2). Known J: Based on the reaction of sea urchin to form a gel. The following formula shows this reaction: t:2(alginate N +-14)
C9,. Ammonium alginate, a derivative from seaweed, is
You can get it from erCk&CO0 with product name 3 upperloid. (Ceramic Composition) The series of conventional paint dispersants and the novel pen ball according to the present invention have essentially the same chemical composition, namely:
Z r 0296, 5% by weight and M (103,515
-% (molar ratio 90:10). Furthermore,
The grinding balls are Hf 02, S! It contains small amounts of oxides such as 02 and CaO, which are introduced along with the zirconia powder when compounding the batch. The MgO level was set to 3.5% because
This is because it has been found that balls with maximum crushing strength are produced when fired in a tunnel kiln at a maximum weight of 1675°C. The presence of MoO in the composition is intended to stabilize zirconia in the cubic form and also to reduce the tetragonal structure that occurs during cooling from the firing temperature.
This is to avoid a change from a monoclinic crystal structure to a monoclinic crystal structure. It is well known in this technical field that zirconia can be stabilized by using CaO, Y203, CeO2, or other materials alone or in combination. These compounds and other stabilizers are also expected to produce zirconia ceramics suitable for use in pen balls. This J: Examination of eel composition is based on the US patent (recurrence 16
- U.S. Patent No. 28,792 and U.S. Patent No. 4,035
, No. 191. (Composition of the slip and its treatment) Examples of the composition of the slip used to obtain conventionally used dispersion medium/milling balls and the composition of the slip used to produce the pen ball of the present invention is as follows. Table 1 (Percentage of heavy use) Conventional dispersion medium components and grinding balls Pen ball 1rcoa A-Grail"147.52 49.84AM
A Grain S 992”221.59 --- tVN] (Ol-1) 2 3.52 2.59 Water
26.06 46.49 S upreroid O, 220, 391) arva
n 7 1.09 ---N 01100SperSe
44 --- 0.69*I CorninqG 1
ass WorkslFJ, monoclinic zirconium oxide. *2 Associat in New Hampshire, USA
cdM ir+erals C01ISO1idate
Monoclinic zirconium oxide manufactured by l1 company. Superloid (ammonium alginate),
Darvan 7, and NopCosperse
44 (the latter two being anionic polyelectrolytes consisting of sodium polyacrylate in aqueous solution) respectively Kelco, R.T., Vanderbil.
t company and l) iamon sllamrock net 1
It is made by water and 1) ar, which is a deflocculant
The amount of Van 7 Rice N0plJSperSe 44 may be varied from the values shown in the table to adjust the density and viscosity of the slip. The batch of dispersion medium and milling balls is subjected to a 16 hour ball mill operation to produce a slip (slurry) having an average particle size of about 2 microns. Typical particle size distributions for conventional milling ball slips and slips of the present invention (designated Pen Ball) are shown in Table 2. The pen ball batch for this invention is produced in a vibratory mill to an average particle size ranging from 1 to about 0.5 microns [1 micron].
The mill operation time required for this is approximately 48~
It is 72 hours. 2 written as a badge for pen ball
This distribution approximately defines the limits of the distributions actually used to make pen balls. When the average particle size of the batch exceeds about 1 micron, J of Example 1 below is used.
: Unless additional treatment is carried out, the resulting ball is too porous to be suitable as a pen ball. Table 2 Batch particle size distribution of slip for producing zirconia dispersion medium/milling balls according to the prior art and pen balls of the present invention = 19 - Curve AI in FIGS. 2 and 3, k, a conventional dispersion formed by the sol-gel process! Figure 2 illustrates a typical particle size distribution of II/milling balls. <Formation of Balls> FIG. 1 illustrates a method conventionally used to form balls, and this method is also used in the present invention (however, the average particle size is reduced). A slip or slurry 10 is placed in a closed container 12. The container 10 can be pressurized by high pressure air 14 supplied to the brushing tube 16 via a valve 18 . This pressurization causes the slip 10 to flow into a manifold 22 containing a number of nozzles 24 for forming drops. The nozzle can be a stainless steel or plastic tube, the larger the opening of the nozzle, the larger the droplet diameter. It has also been found that drop size is also influenced by drop rate, with rates of 2-3 drops per second being typical. When droplets 26 from nozzle 24 enter CaCL2 vessel 28 within vessel 30, an exchange reaction with ammonium alginate occurs, gelling the slip. The depth of the container 28 is approximately 1
6 inches, sufficient for the gelled balls to be produced without being damaged by colliding with the bottom of the container and other balls. The gelled balls 34 are recovered from the solution, washed with water to remove residual CaC9J2, and placed in a dryer at approximately 100° C. to remove moisture. (Firing) The balls 34 dried as described above are then placed in a stabilized zirconia crucible and subjected to 1 to
fired in a tunnel kiln. Room temperature 110℃/Duck 870℃ - 1675℃, held at 1675℃ for 4 hours. Otogeko 1
340℃ 95℃/hour > 870℃, 115”C;
When the crystal is fired in a room, a ball is formed which is entirely composed of equiaxed zirconia and contains tetragonal and monoclinic precipitates. If it is desired to increase the toughness of the ball, hold it in a temperature range lower than 1340'C.
The cooling conditions may be changed if the amount of precipitates increases. After firing, the porosity of the dispersion/grinding ball is generally about 20% by volume when measured by optical image analysis of the polished part. Optical image analysis shows that [ )
1g1tal E equipment Corpora
Commercially available from Non, Lysostructural Analysis i1 (l
eitz texture analysis
System, Model No. 1980) and a programmable database [1 Setsa (Model PI) P11/3
4) using an image analysis computer system consisting of: Optical image analysis methods are known, for example, J.
[Mathematical form and image analysis (lyjat
Hematical Morphology and■m
age analysis) J (U.S. New
York, Δacademic press 1982
Published in 2013). Balls suitable for use in pen balls according to the invention are approximately 8
%. Such balls must have a porosity of less than 10%. Such balls can be prepared by treating conventional grinding balls to reduce their porosity, as shown in the examples below. Example 1 Reducing the porosity of a prior art ball after firing to a level lower than 8 volume percent, and in some cases 0.5 percent 1, suitable for the present invention. To achieve this, heating and isostatic pressure can be used. This technique itself is already known and is described, for example, in U.S. Pat. No. 3,562,371. By combining the high temperature and high pressure of heating and isostatic pressure, an almost completely dense ball can be produced. Pressure strip 1
is effective in processing prior art dispersion tX/milling balls to produce the pen balls of the present invention. Room temperature 27°C/min 1600°C Hold at 1600°C for 2 hours ---→ → Hold 27°C/min 1200°C Hold at 1200°C for 45 minutes ---1-----) 13°C/min Room temperature- -→ Argon pressure of 30,000 ps at 1600℃
i (2100/rg/ci). Temperatures considerably lower than the normally adopted 1675°C (for example, 1550°C)
By uniformly pressurizing the pre-sintered balls at a temperature of 100.degree. Low temperature sintering produces balls in which almost all the porosity is at the grain boundaries rather than within the grains. Heating and balanced pressure is very effective in removing porosity existing at grain boundaries, and has a much smaller effect on pores inside the grains. Excessively non-spherical pen balls meet ASTM D1155-5
The process can be performed using a vibrating table as shown in 3. -25-, A. 24- (How to form the ball) Fine 1. <Many methods are described in the literature for forming spheres from powders, and 14 other possibilities are also possible. Examples of the latter include (1) extrusion molding of a rod-shaped object with a circular cross section, cutting it into small pieces, and firing it before and after cutting, and (2) dry pressing of powder to form precise cylindrical objects. and in each case: b1
Strong crushing of the cylinder after firing (including removing at least 40% of the material) to obtain the desired spherical shape.
is necessary. Several methods are described in the literature for forming globules by tumbling dry or wet fine powders in rotating containers and consolidating them. This method is generally referred to as [ballin (1) J] or [pelletizino J].
f 7incQxide powders) l (I
&ECproCessDesiqn &Rev,,5
(1) 10-14 (196G)) 26 describes a binderless dry process for forming zinc oxide pellets from submicron powders. In this method, seeds consisting of pre-compacted zinc oxide particles of approximately 200 mesh size are used.
d) is directed to a drum containing dry submicron zinc oxide powder. Then, as the sealed drum rotates at a constant speed of 33 to 110 rpm, the seeds grow by consolidation into spheres. Kapur and I” urstenau [Particle size distribution and velocity relationship in the core region of turbid pelletization (S
ize 1) istrN] 吋i0n and K 1n
etic Relationship in tl>e
Nuclei Region of Wet pel
let:1zation) J (I&FCProce
ss Design&Rev, 5(1) 5-10
(1966)), balls are produced by tumbling wet limestone powder in a rotating drum. In this method, 40-50% by volume of water is mixed with limestone and then the wet batch is passed through a screen to obtain fine particles. The particles are then tumbled within a drum containing a lifting bar on its inner periphery. As the drum rotates, the material therein forms condensates in the form of small spheres, the size of which increases as the drum rotates at higher speeds. In this way, spheres with a diameter of up to 5 mm have been obtained. Williams [Manufacture of spherical objects of controlled size from powder materials by the planetary rotation method (FabricaN
onof 5pheresof Controlled
3ize from Powder Materi
als lay P 1anetaryRollin(
] TechniqLIe) J (Proc, Br1
t, Ceram, 3 QC,, N 0012.1969
A similar method for producing ceramic spheres is also described in the March 2013 issue. In this method, the seeding spherules are added systematically while a batch of powder/binder is added to the seeding spherules.
Ti stars Consolidate and grow in a rotating mill. The rate of consolidation is controlled by adjusting the concentration of n-decanol (binder) in the powder feedstock. In order to control the production, it has been shown that it is necessary to sequentially vary the concentration (level) of the binder as follows: 1. To form the seed spheres, High Kanmaro 2.3! For continuous addition, medium concentration 3, to obtain spheres, low 81. [Formation of spheres from fine solids in suspension (F.
organization of 5pheres from
F 1nely D 1vidcdSolids in
1quid 3uspension) J (D
esi! ] 11 & Development, 6 (
1) 146-54 (1967)) discloses a method for forming spheres from powder in suspension. In this method, the dispersed powder is solidified by stirring the suspension with a small amount of a second liquid, which selectively clouds the solids and does not mix with the first liquid. It becomes a spherical object. During stirring, the powder becomes coated with the second liquid and condenses to form spheres. In the study of this paper, the first liquid is carbon tetrachloride and the second liquid is water, methanol or a mixture thereof. A typical batch composition is as follows. Sand 10 g Carbon tetrachloride 75 cc Water 2 cc Several other gelation-based methods for producing ceramic balls have also been reported. 1.Chemical F I
owsleet Conditions for p
reparing Urania S phares
by internalGelation)J
(1 & FCProduct Res. Dev, 19(3) 459-67 (1980)), UO2 balls are produced by chemically gelling droplets of uranium nitrate. Hexyrimethylene 1-lamine (IMTA) dissolved in the uranyl nitrate solution decomposes to release ammonia, which precipitates a hydrated UO2 gel. In this method, the droplets are heated and deposited in a Iζ trichlorethylene bath, resulting in decomposition of 1-1 M TΔ. The resulting spheres are washed with a 0.5M sodium hydroxide solution, then dried and fired. 1J-T, U.S. Pat. No. 4, by Lardwick et al.
No. 182,627, a pen ball made of tungsten carbide bonded with Kobal 1 is produced by a gel-based process. In the method of the patent, tungsten carbide particles, guar rubber, cobal nitrate 1
-J: Drops are formed from a mixture consisting of a soluble cobalt salt and wetting agent. Thus, the droplets gelled upon contact with an 8N aqueous solution of sodium to lithium hydroxide. After washing with water, the jqed spheres are air-dried and fired at ambient temperature. In addition, the dry pressurization of the cylindrical object as mentioned above is 5000 ~
Cart+owax 20M (Cart+owax 20M) Pressurized to 2000psi
) can be carried out using a spray-dried granulated powder containing: Also, Mae i! Ii The extrusion molding of rods with circular cross sections such as
fl Parent's Me1-Sale 20M (M eth
It can be carried out using a powdered batch containing ocel 20M). Prior to extrusion, mixing is preferably carried out in a Muller mixer. As mentioned above, all of the methods described above apply to the J: Huh? marked as pen ball in Table 2. By using a batch composition milled to an X particle size distribution, it can be used to prepare blanks for zirconia pen balls. Example 2 This example (well, it is for showing another method for forming the pen hole of the present invention). Pressure methods are not included. This example employs a small average particle size zirconium oxide containing batch as described above in connection with Table 2. This example contains 3.5 weight percent Moo. 4540 cc of water and 125 cc of N 0pCO8p
erSe 44 (anionic polyelectrolyte consisting of sodium polyacrylate in aqueous solution) at 10.950
A suspension was prepared by stirring with g of zirconia (Zircoa A-Grain) and 568 g of magnesium hydroxide. This mixture was placed in a vibratory mill containing a grinding media consisting of stabilized zirconia h11 and ground for 72 hours until an average particle size of 0.60
Micron slips were produced. Curve C in FIGS. 2 and 3 shows the particle size distribution of the zirconium oxide-containing batch of this example. Also, curve B in Figures 2 and 3 does not show the particle size distribution of other batches with average particle sizes slightly smaller than 1 micron. Curve B is believed to represent the upper limit of the average particle size for a batch that would yield a low porosity pen ball without the use of heat isostatic pressing. (It will be appreciated here that this average particle size is less than one-half the average particle size of conventional ones for making dispersion TS/milling balls. 32-5675 cc of water 85g of Superloi (1(
In Preparation 1], a solution containing ammonium alginate was mixed with the milled batch described in ]-. The resulting slip was passed through a 325 mesh screen.
The slip was vacuumed in a closed container to remove air. Next, as shown in FIG. 1, the suspension is pumped into the duct 22 and a plurality of nozzles (made of 22-gauge stainless steel MN) by the pressure of the air 14 to form droplets for gelation. Formed. ca ci. Consisting of an aqueous solution of 1.073/cm
Gelation occurred when droplets 26 were dropped from nozzle 24 (see Figure 1) into a bath 28 having a specific gravity of 100%. The treated T culm was deformed and turned into a smelt.Next, the droplets were thoroughly washed in running water, and then placed in an electric dryer at 100°C and kept overnight.The dried droplets were 1675 in a gas-fired tunnel kiln under the firing conditions described above in a stabilized zirconia crucible.
It was fired at 1°C. It was found that the pen ball was made of equiaxed zirconia, and a small amount of fine tetragonal zirconia was precipitated within the equiaxed crystal. The apparent specific gravity of the ball was 5-68 g/Cm3 when measured using mercury boroshimake. Moreover, the average diameter was 1.40 mm, and the standard deviation was 5.2%. A pen ball is placed between two bonded tungsten carbide plates and a compressive force is applied using an Instron mechanical testing device (crosshead speed 10
, 2 mm/min). If so, the plate used for the measurements contained 6 percent cobalt, had a hardness of 90 RC (Rockwell hardness), and was treated to a hardness of 0.05 micron. The average breaking strength of the 10 balls was 94.4 Bond with a standard deviation of 11.2 percent 1-. Optical image analysis of the polished portion of the ball showed that the average porosity of the ball was 1.01% by volume with a standard deviation of 25.8 percent. The average pore diameter is 2.73 microns (standard 11
deviation 4.0%), and the main pore diameter was 2.25 microns. These lots of pen ball blanks have a surface roughness of 0.
．． It was finished to a size of 10 to 0.15 microns to produce a pen ball for use in rolling ballpoint pens. Also,
Another lot was finished to a surface roughness of 0.04 to 0.
05 micron and used for a ballpoint pen using viscous ink. Now, FIG. 4 shows the tip of a typical ballpoint pen using the pen ball of the present invention. Reference numeral 50 designates the entire tip, which is often made of stainless steel. Hole 52 receives a core;
The lead is adapted to be connected to a reservoir for writing ink. An ink flow channel 54 is formed in the tip 50 and is typically disposed within a plastic sheet 56. The edge of the tip 50 is stamped at 58;
A pen ball 60 is rotatably held within a socket as shown. Thus, the present invention is constructed of fully or partially stabilized zirconium oxide and formed into a spherical ball by any means to transfer the ink from the ink reservoir of the pen to the writing surface. The present invention provides a ceramic body used for quantitative transfer to paper (for example, paper). The composition of the liquid transfer ball of the present invention can be expressed by the following general formula. (Zr 02 ) l−x (Ry Oz ) x where R is +2. +3 or +4
is at least one element selected from a group of elements that form a cation having a valence of about 0.
represents a number having a value from 05 to approximately 0.3, and
y and Z represent numbers having values sufficient to render RVO7 electrically neutral. Examples of elements suitable for R are magnesium, calcium, and yttrium. Threadium and lanthanide series elements (e.g., cerium, neodymium, tetranomalium, itterbiulz)
), and these elements are respectively oxide MgO
, Ca O, Y203 , SC203, CQ 02 ,
Nd203. Sm 203 and Yb2O3 are produced. The first two oxides are oxides of elements from group TIA of the Periodic Table; the other oxides are oxides of elements from group IIIB of the Periodic Table (including the lanthanide series). CR in Cleveland, Ohio, USA
"andbook of C" published by CP ress
(See Hemistry and Pbysics, 50th edition, page B-4). Moreover, these oxides, for example, M
(A mixture of IQ and Y2O3 is also suitable. In this case, ×
are values in the same range. According to the invention, a zirconium oxide body with highly tailored physical and chemical properties provides an optimal combination of all the properties required for excellent behavior as a ball for ballpoint pens. The optimum properties exhibited make the zirconium oxide body significantly more suitable for the application than other materials. For example, a tungsten carbide ballpoint pen ball designed to deliver 0.19 g of ink per hour will wear out the socket 1 and increase the ink transfer rate to keep the contained ink flowing for 5 to 6 hours. Consume with. In contrast, the ZrO2 ball of the present invention supplies ink for 13 to 16 hours, with an initial transfer rate of 0.19 g/hour and a final transfer rate of 0.22 g/hour. Tungsten carbide balls and other +J II balls have the tendency to initially corrode when they come into contact with water-based inks (5% 1-1 NO
3 solution after 5 minutes). Also, if tested in acetic acid solution,
The tungsten carbide balls showed no severe corrosion for 5 minutes to 24 hours. In contrast, 7r 02 is completely inert to the action of acid resistance. Additionally, Austechai 1 stainless steels are relatively soft and do not have abrasion resistance to contact with surfaces such as paper. On the other hand, 75-9
ZrO2, which has a hardness of 5RC, is unaffected by most contact surfaces. The low porosity (less than 8%) zirconium oxide pen ball of the present invention consists of zirconium oxide and a stabilizer, It can be produced from conventional slips by heating and isostatically pressing conventional dispersion medium balls having a particle size distribution as shown by curve A in FIGS. A slip of zirconium oxide with a particle size distribution as shown by curve C in Figures 2 and 3 is prepared and then formed into balls using the conventional sol-gel process (10 and It is also possible to produce 1 q of balls with a porosity as low as about 8%.

[Brief explanation of the drawing]

FIG. 1 illustrates an apparatus conventionally known as the sol-gel method for producing dispersion medium/milling balls, which is also employed for producing the pen balls of the present invention. be. FIG. 2 is a graph showing the particle size distribution of the slip shown in Table 2, where the curve △ is the one that exceeds the conventional dispersion medium/milling ball manufactured, and the curves B and C is for manufacturing the pen ball of the present invention. Figure 3, like Figure 2, shows the particle size distribution in Table 2 for the water type, but the vertical axis shows the abundance in percent 1 to percent of particles smaller than the particle size. Representation, also
The horizontal axis is not on a logarithmic scale 39- as shown in FIG. FIG. 4 is a sectional view showing the tip of a typical ballpoint pen in which the pen ball of the present invention is used. 50...Ballpoint pen tip 60...Pen ball=
40-1 Orange (Mi7Dnn Fig, 2

Claims (1)

[Scope of Claims] (1) A liquid transfer ball characterized in that it is made of ceramic containing zirconium oxide. (2) The liquid transfer ball according to claim 1, wherein zirconium oxide is the main analytical component of the ceramic. (3) A liquid transfer ball according to claim 2, wherein the ball has a porosity of less than 8 percent as measured by optical image analysis of the polished portion. (4) The zirconium oxide is at least partially stabilized by a stabilizer that forms at least one phase selected from equiaxed zirconia and tetragonal zirconia at high temperatures, and when cooled to room temperature, the phase is stabilized. The liquid transfer ball 3° (5) according to claim 3, wherein the composition of the ball is a molecular formula (%) (%) (wherein R is a group 1TA of the periodic table, A minor element selected from the group consisting of Group 11113 and the lanthanide series (both are one element that forms a stable +2, +3 or +4 valence cation in an oxide, ×
is a number having a value of about 0.051 to about 0.3,
5. The liquid transfer ball according to claim 4, wherein (2) and 1 are numbers having values necessary to make (RV Ol) electrically neutral. (6) The liquid transfer ball according to claim 5, wherein the stabilizer is selected from the group consisting of CaO, MgO, Y203, and mixtures thereof. (7) Stabilizers include CaO, MaO and Y2O3
oxides selected from the group consisting of M!, and the weight of each of these oxides is M!, based on the total weight of the ball. ] 02.6-5.5%, CaQ'3.0-10
%, and Y203 4.0 to 16%. (8) The liquid transfer ball according to claim 4, wherein the ball is formed from zirconium oxide powder having an average particle diameter of much larger than about 1 micron. 9. The liquid transfer ball of claim 4, wherein the ball is formed from zirconium oxide powder having an average particle size of no greater than about 0.6 microns. (10) forming a sintered body of at least partially stabilized zirconium oxide, the sintered body exhibiting porosity as measured by optical image analysis of the polished portion;
5. The liquid transfer ball according to claim 4, which is manufactured by applying heating and isostatic pressure to the sintered body to reduce its porosity. (11) The sintered body is formed from particles having an average particle diameter of less than 1 micron and a porosity of at least about 10% before heating and isostatic pressing.
Ball for liquid transfer as described in section. (12) It has a hollow tip arranged to be connected to the liquid storage part, and a liquid transfer ball placed in a protruding shape on the hollow tip, and the liquid transfer ball has a A device for transferring a liquid, characterized in that it is formed from a ceramic containing zirconium oxide. (13) The device according to claim 12, wherein zirconium oxide is the main analytical component of the ceramic. <14) The apparatus of claim 13, wherein the ball has a porosity of about 8% J: as measured by optical image analysis of the polished portion. (15) The device according to claim 14, wherein the zirconium oxide is at least partially stabilized by a stabilizer. 3-